The present invention is in the field of testing movable window seals of the type found in sliding vehicle windows.
The xe2x80x9cglass runxe2x80x9d in an automobile door is the rubber seal mounted in the sliding window channel in the window frame. There is usually a xe2x80x9cbelt sealxe2x80x9d along the lowermost edge of the window frame through which the window is extended and retracted from the interior of the door.
The sliding/wiping seal fit between the glass run and belt seals and the edges of the window creates frictional wear on the seals, which are expected to withstand tens or hundreds of thousands of cycles while maintaining an effective seal with the window. The reliability of the seals and their resistance to wear is therefore critical to the long-term operation of the entire window assembly. In an automobile the window assembly is a fairly integral part of the door, and repair or replacement of the seals can be difficult and expensive.
The current method of testing the effectiveness and wear life of the glass run and belt seals is to put the seals in an actual production-line door and to test them over hundreds or thousands of cycles at the automobile manufacturer""s facility. There are a number of problems with this method. First, if the seal is defective, the entire door and window frame must be disassembled, and the seal must be replaced, returned and diagnosed by the seal manufacturer. Second, this testing method cannot anticipate the minimum and maximum tolerance variations from door to door. Third, the window actuator motors are prone to failure, and because they overheat easily they are operated for seal testing at about one cycle per minute. This is very slow when a seal""s failure limit of tens of thousands of cycles is being tested.
Another difficulty in testing glass run seals is the frequent need to test them under specific environmental conditions, for example hot conditions simulating desert use and cold conditions simulating winter use. Current methods of testing make it difficult and expensive to test under these conditions.
In its broadest form the invention is a machine for testing glass run seals with a simulated, adjustable-tolerance window frame, using an associated high cyclic rate drive to reciprocate the window glass in the simulated frame""s glass run. The simulated glass run holds sample seals, and is preferably adjustable to accommodate different seals or to vary seal tolerances.
In a preferred form the inventive testing machine is a self-contained unit comprising both the simulated glass run and window drive. The self-contained machine can be mounted on wheels for portability, for example allowing the testing machine to be rolled into an environmental test chamber simulating a real life window operating environment.
In a further preferred form the window drive is not an actual door-mounted window actuator, but a stronger, faster, adjustable speed motor, much more robust than the typical window actuator. Rather than operating at one cycle per minute as is done with the easily-overheated window actuators, the testing machine drive motor has been used to cycle the window as fast as twelve cycles per minute, greatly reducing test time.
In another preferred embodiment, the simulated glass run comprises an easily-adjusted set of spacers and seal mounts simulating the vertical glass run channels on the sides of the window, and optionally the upper edge of the window and the belt seal along the lower edge. By adjusting spacers in the frame, or by adjusting the frame itself, the simulated glass run can be adapted to test both different seals and different window types or models.
In a further preferred form a wear-measuring device such as a load cell is mounted in the drive system to measure progressive changes in window closing effort between the window and seals over hundreds or thousands of cycles.